Along with development of mobile device technology, smart phones are continuously popularized, and play a more and more important role in daily lives of people.
At present, a smart phone usually adopts a design with three virtual keys (i.e. touch keys), and the three virtual keys are arranged below a display area of the smart phone, wherein each of the virtual keys is configured to realize different functions. For example, the three virtual keys are configured to realize functions of returning to a previous page, returning to a desktop menu page and switching a task, respectively. When a user touches a virtual key, the smart phone acquires a corresponding operation signal, and realizes the corresponding function according to the key on which the operation signal acts.